Hisayoshi Nozaki and colleagues have just described some Volvox samples from two lakes and a pond in Japan.
The newly collected strains have a lot in common with another recently described species, Volvox ferrisii, but there are some important differences as well:
…it could be clearly distinguished from all previously described monoecious species of Volvox sect. Volvox by its small number of eggs or zygotes (5–25) in sexual spheroids, with short acute spines (up to 3 μm long) on the zygote walls and elongated anterior somatic cells in asexual spheroids.
In spite of these differences, Nozaki and colleagues stop short of calling the newly collected strains a new species. Why?